Strabismus is a disorder of the muscles of the human eye and may cause the misalignment of the two eyes. This condition may be called “cross eyes” or “wall eyes.” A person so afflicted may experience difficulty in focusing both eyes on the same point at the same time. As a result, the brain accommodates by recognizing the images visualized by only one of the two eyes.
Such a malady has been treated by means of surgery to help correct the condition.
There have also been proposed a variety of different therapy techniques for eye maladies. For example, reference may be made to the following U.S. patents, each of which is incorporated herein by reference:
U.S. PAT. NO.ISSUE DATE4,294,522Oct. 13, 19814,536,065Aug. 20, 19854,756,305Jul. 22, 19885,206,671Apr. 27, 19935,264,877Nov. 23, 19935,360,438Nov. 1, 19945,452,026Sep. 19, 19955,550,602Aug. 27, 19965,877,840Mar. 2, 19995,900,921May 4, 1999
In order to attempt to avoid surgery to correct the disorder of strabismus, a technique has been developed to help a person afflicted with this malady to strengthen his or her eye muscles to help focus the eyes properly. The technique employs the use of images of red and green colored symbols or designs, which are viewed through a pair of eyeglasses having one green lens and one red lens. The person attempts to match the colors of the symbols while wearing the eyeglasses. In so doing, one eye is covered with a green lens, and the other eye is covered with a red lens.
As a result, the person wearing the pair of red and green colored eyeglasses see the red design through the green lens, and the green design through the red lens. In this regard, the red design may not have sufficient contrast using the red lens to be able to allow the person to distinguish the image of the red design. Thus, the red design may not be seen through the same colored red lens. Similarly, the green lens was intended to prevent the green image to be seen through the green lens. This technique tends to cause the person to use and to coordinate the use of both eyes to see the complete image. This exercise then tends to train the muscles of the eyes to focus on an object, and thus the brain tends to take into account the images received by both eyes in a proper manner.
However, unlike the red lens, the green lens may not completely conceal from view the green design for at least some applications. Thus, the person may still be able to see a faint image of the green design through the green lens in certain situations.
As a result, such a technique has not been found to be entirely satisfactory for some applications. For example, when children or certain other people use this technique, the faint green image seen through the green lens at least somewhat defeats the purpose of strengthening the eye muscles by causing the person to use both eyes for focusing. In this regard, the user may still be able to see both the red and green images with the same eye, even though to a limited extent, by using only one lens (the green lens).